Cell-based gene transfer is a known, albeit relatively new and experimental, technique for conducting gene therapy on a patient. In this procedure, DNA sequences containing the genes which it is desired to introduce into the patient's body (the transgenes) are prepared extracellularly, e.g. by using enzymatic cleavage and subsequent recombination of DNA with insert DNA sequences. Mammalian cells such as the patient's own (i.e. autologous) or cells from another individual (i.e. allogenic) cells are then cultured in vitro and treated so as to take up the transgene in an expressible form. The transgenes may be foreign to the mammalian cell, additional copies of genes already present in the cell, to increase the amount of expression product of the gene or copies of normal genes which may be defective or missing in a particular patient. Then the cells containing the transgene are introduced into the patient, so that the gene may express the required gene products in the body, for therapeutic purposes. The take-up of the foreign gene by the cells in culture may be accomplished by genetic engineering techniques, e.g. by causing transfection of the cells with a virus containing the DNA of the gene to be transferred by lipofection, by electroporation, or by other accepted means to obtain transfected cells, such as the use of viral vectors. This is sometimes followed by selective culturing of the cells which have successfully taken up the transgene in an expressible form, so that administration of the cells to the patient can be limited to the transfected cells expressing the transgene. In other cases, all of the cells subject to the take-up process are administered.
This procedure has in the past required administration of the cells containing the transgene directly to the body organ requiring treatment with the expression product of the transgene. Thus, transfected cells in an appropriate medium have been directly injected into the liver or into the muscle requiring the treatment, or via the systemic arterial circulation to enter the organ requiring treatment.
Previous attempts to introduce such genetically modified cells into the systemic arterial circulation of a patient have encountered a number of problems. For example, there is difficulty in ensuring a sufficiently high assimilation of the genetically modified cells by the specific organ or body part where the gene expression product is required for best therapeutic benefit. This lack of specificity leads to the administration of excessive amounts of the genetically modified cells, which is not only wasteful and expensive, but also increases risks of side effects. In addition, many of the transplanted genetically modified cells do not survive when administered to the systemic arterial circulation, since they encounter relatively high arterial pressures. Infusion of particulate materials, including cells, to other systemic circulations such as the brain and the heart, may lead to adverse consequences due to embolization, i.e. ischemia and even infarction.
The acute respiratory distress syndrome (ARDS), the clinical correlate of severe acute lung injury (ALI) in humans, is an important cause of morbidity and mortality in critically ill patients (1-4). Infectious etiologies, such as sepsis and pneumonia (including influenza and SARS), are leading causes of ALI/ARDS (1, 2). Histologically, ALI/ARDS in humans is characterized by a severe acute inflammatory response in the lungs and neutrophilic alveolitis (1). Inflammatory stimuli from microbial pathogens, such as endotoxin (lipopolysaccharide, LPS), are well recognized for their ability to induce pulmonary inflammation, and experimental administration of LPS, both systemically and intratracheally, has been used to induce pulmonary inflammation in animal models of ALI (5-9).
The physiological hallmark of ARDS is disruption of the alveolar-capillary membrane barrier (i.e., pulmonary vascular leak), leading to development of non-cardiogenic pulmonary edema in which a proteinaceous exudate floods the alveolar spaces, impairs gas exchange, and precipitates respiratory failure (1, 10, 11). Both alveolar epithelial and endothelial cell injury and/or death have been implicated in the pathogenesis of ALI/ARDS (1). However, despite decades of research, few therapeutic strategies for clinical ARDS have emerged and current specific options for treatment are limited (12-16). ARDS continues to be an important contributor to prolonged mechanical ventilation in the intensive care unit (ICU), and ARDS-associated mortality remains high at 30-50% despite optimal ICU supportive care (1, 13, 14, 16).
ARDS is a complex clinical syndrome which is initiated by injury to the lung, often in the setting of pneumonia and/or sepsis, and aggravated by ventilator-induced injury. Some of the early feature of ARDS can be reproduced by administration of bacterial endotoxin (LPS), which acts via Toll-like receptor 4 (TLR4), to increase the expression of inflammatory cytokines and chemokines, and upregulate leukocyte adhesion molecules, results in EC activation (5-9, 57).
It is an object of the present invention to provide a novel procedure of cell based therapy or cell-based gene transfer to mammals, for the treatment of lung diseases or disorders.
It is a further and more specific object of the invention to provide novel procedures of cell-based gene therapy utilizing dermal (or other) fibroblast cells, EPCs, or MSCs, for treatment of lung diseases or disorders.
It is a further object of the invention to provide novel genetically engineered cells containing transgenes expressing angiogenic factors for treatment of lung diseases or disorders.
It is a further and more specific object of the invention to provide novel uses and novel means of administration of angiogenic factors in human patients for treatment of lung diseases or disorders.
It is a further object of the invention to treat or prevent pulmonary hypertension utilizing novel therapies, including cell therapy and cell-based gene therapy.
It is a further object of the present invention to treat or prevent Acute Respiratory Distress Syndrome (ARDS) utilizing novel therapies, including cell therapy and cell-based gene therapy.